Complete the crossword, then click on "Check" to check your answer. If you are stuck, you can click on "Hint" to get a free letter. Click on a number in the grid to see the clue or clues for that number.

1								2
				3													4
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		6										7
				8
	9
10																11
12
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		14
15										16
		17
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 Check 

Across: 1. Animal that feeds on other animals. (9) 3. Energy flow relationship starting with a green plant followed by a series of animals. (4,5) 6. Chemical element needed by all organisms to make protein. (8) 7. Animal that eats both plants and animals. (8) 8. Chemical substance needed by a living thing to stay alive and grow. (8) 9. Process by which green plants convert light energy to chemical energy stored in starch. (14) 12. Process by which all organisms release the energy stored in food. (11) 13. Animal that hunts other animals for its food supply. (8) 14. Micro-organism that obtains its energy by breaking down dead organisms or waste material. (10) 15. Animal that feeds only on plant material. (9) 16. Simple plants, sometimes microscopic, that lack chlorophyll. (5) 17. General name for an organism unable to photosynthesise and dependant on a ready-made food supply. (8) 18. Chemical compound containing nitrogen that is present in body building foods. (7)

Down: 2. Removal of waste products from an organism's body. (9) 4. The total mass of living matter. (7) 5. Chemical containing nitrogen produced during the decomposition of nitrogenous waste by bacteria. (8) 8. Process by which bacteria in soil convert ammonium compounds to nitrite, and nitrite to nitrate. (13) 10. Animal that is hunted by other animals. (4) 11. Microscopic organisms, normally unicellular, and lack chlorophyll. (8) 13. Green plant which makes food by photosynthesis. (8)